Reading books can be enjoyable and informative. In particular, reading a book to a child can be a pleasant way to spend time with the child, while at the same time calming the child and helping the child to mentally prepare for sleep.
However, light is required so as to read a book, and having a bright light on in a child's room is generally not conducive to mentally preparing the child for sleep. Also, having a light on in a child's room can tend to distract the child, by allowing the child's gaze to wander to various objects in the room, thereby making it more difficult for the child to concentrate on the story being read from the book.
One approach is to darken the room and illuminate the book using only a highly focused light source, such as a light source clipped or otherwise directly attached to the book. However, a highly focused light source can become hot, and can pose a danger to the book, the reader, and/or the child. Also, a highly focused light source can create harsh shadows and other visual effects within the room that a child might find distracting, disturbing, or even threatening.
Some approaches attempt to minimize distraction in a lighted room by including sources of illumination in the book itself, thereby adding visual interest to the book and helping to hold the child's attention. Typically, individual sources of light are positioned at strategic locations within illustrations included on the pages, thereby enabling starts to twinkle, fireflies to blink, and such like. The light sources can be phosphorescent indicia, LED lights, optical fibers, and electro-luminescent lights, among others. Some of these approaches enable a user to interactively control the illumination, for example by pressing switches embedded in the pages. While these approaches can help to avoid distraction by adding visual interest to the book, they do not provide a general, uniform illumination of the pages in the book that would eliminate the need for external lighting.
Other approaches attempt to avoid external lighting by embedding one or more sources of light within the book that provide full-page illumination. For example, some approaches include a lamp embedded at one corner of the book or in the spine, and positioned so as to shine light across the pages as they are read. However, these approaches do not provide uniform illumination of the pages. Another approach uses electroluminescent sheets embedded in the pages to provide uniform, back-lit illumination. However, electroluminescent light sources have a finite lifetime, and fade in intensity with age. In general, while these approaches provide illumination for reading, and thereby eliminate the need for external lighting, they do little if anything to enhance the visual interest of the book.